NJS Kitanihon Onkyo CO., LTD.(Japanese Yamagata Prefecture Sakata City)

Electrical impedance characteristics are shown typically in Fig. 1 and indicate changes in the electrical impedance due to voice coil frequency. Rated impedance is the lowest electrical impedance value in the frequency range above the lowest resonant frequency.

This is the specified power input for average speaker performance. It can be calculated using the following equation.

If the nominal power input is exceeded for an extended period of time, please note that thermal breakdown of the voice coil, or mechanical breakdown due to diaphragm edge or damper fatigue may occur and the speakers may not operate normally.

Maxmam Power

This is the maximum power input allowed when a program signal is fed to the speaker unit for a one-minute period and this is repeated 10 times at two-minute intervals.

This is the lowest frequency in the frequency band where the electrical impedance characteristics of the voice coil are at their maximum.
The fo is the resonant frequency resulting from the vibrating mass and the stiffness of the diaphragm edge and damper, and is an important value that indicates the speaker unit’s lower playback.

Sound pressure level(SPL)

This value is gained by averaging the sound pressure levels at 4 individually determined frequencies.

Frequency characteristics are shown in the graph showing changes in frequency against changes in sound pressure level. For speaker units, the unit is installed in a standard sealed box (a box complying with JIS provisions), and measurement is performed at 1 m distance, on axis, with 1 W input in an anechoic room (dead room). However, when speaker units are actually included in a set, frequency characteristics will vary due to the baffle shape, parts design, the area and shape of the grille openings, and the difference in cabinet capacity. You may not be able to compare frequency characteristics in this catalog with data from other companies because of differences in the anechoic room environment, and the baffle shape of the JIS box, etc.